Telephone dial



United States Patent 3,043,917 TELEPHONE DIAL Willy Lohs, Walter Paui,and Heinrich Kallhardt, Munich, Germany, assignors to Siemens & HalskeAktiengesellschaft, Munich, Germany, a corporation of Germany 7 FiledSept. 2, 1958, Ser. No. 758,522 Claims priority, application GermanySept. 10, 1957 9 Claims. (Cl. 17 9-90) This invention is concerned witha telephone call transmitter of the finger-wheel or finger-disk operatedtype, provided .with an impulse transmitting device and a governor forregulating the operation thereof.

In known transmitters of the above indicated kind, the spindle for thegovernor, which is actuated-by a worm drive, is disposed perpendicularto the spindle for the im pulse transmitting device. The assembly ofdials of this kind is involved because it requires keeping bf accuratetolerances. The worm drive is moreover relatively inetficien't becausepart of the force applied for rotation is dissipated in the form ofaxially effective components.

There is also a call transmitter known in which the drive for thegovernor and for the impulse device is effected over a two-stage-spurgear wheel. The spindles for this drive are provided with extensionswhich are journalled in two plates. The assembly of such transmitterdevice is likewise very involvedbecause the two plates must be adjustedaccurately one with respect to the other and their structure must be ofhighest accuracy. Such a device exhibits the further disadvantage-thataccess to the gear parts is difficult and that one of the plates must beremoved to effect exchange or replacement of individual parts.

The object of the invention is to provide a telephone call transmitterwhich is characterized by simple assembly, easy accessibility of gearparts and reliable operation, without requiring any particularmaintenance. This object is realized by disposing the spindles for thegears with one end thereof secured in the mounting frame or base andfreely extending from such base.

The disposition of the spindles with the associated gearv parts freelyextending from the base may be effected very simply. The gear parts arein the assembled device very well accessible. In accordance with afurther feature of the invention, the assembly is simplified byembedding the spindles in the base or frame incident to fabrication ofthe latter, for example, as a diecast part.

Maintenance of the gears becomes practically superfiuous by forming theoperating parts of'all gear wheels and pinions of non-metallic syntheticmaterial, thus eliminating the lubrication required in the case ofmetallic gear wheels. The spindle of the finger disk and the drive gearwheel are coated with a nonmetallic synthetic material, thereby securingproper operation of such spindle in the base without requiring bearingsleeves made of bronze or the like inserted in the base. The spindle maymoreover be made as a diecast part, thereby reducing the cost offabrication.

The stop for limiting the rotation of the fiinger disk is disposed inthe marginal portion thereof, whereby the gears are stopped with littlestress since the mass forces to be controlled appear at points where thestop for limit embracesthe governor spindle 2 approximatelysemicylindrically, such extension serving for securing the member 7which forms a cylindrical raceway for the governor,

the member 7 being stamped from a plate, and being fastened by means ofscrews 5 and 6.

Rotatably journalled in the frame is the main shaft 9 which is fixedlyconnected with the finger disk 8. This shaft is provided with a picketof non-metallic synthetic material 10. The good slippingproperties ofthe synthetic material (a p'olyamide will preferably be used) make itunnecessary, as already mentioned before, to insert' individual bearingbushings in the frame and make it possible toform' the shaft as adiecast part, resulting in simplication of assembly operations and inreduction of costs.

At its free'end, the main shaft 9 is provided with a casing 12 securedto the shaft by means of an angular member 11, the casing 12 containingrestoring spring 13, one end of which is anchored'in the frame while theother end is anchored in the casing 12. The spring casing .12 isprovided with extensions 14 which project through openings 15 formed ina gear wheel 17 disposed adjacent the casing 12 and rotatably secured inplace by means of screw 18 and washer 19. Rotation of the finger disk 8will cause rotation of the spring casing 12 and the extensions 14 of thespring casing will take along and rotate the gear wheel -17correspondingly. The structure provides a satisfactory connectionsecuring the parts for reliable rotation while requiring merely acentral bore in the gear wheel, such bore being for manufacturingreasons preferably a non-circular opening.

The gear wheel 17 meshes with pinion 20 which is journalled on thespindle 3, the pinion having a bushing 21 integral therewith which iscoupled to a gear wheel 22 by means of a clutch spring 23. A split ring24 secures the gear wheel 22 against displacement in axial direction.Between the split ring 24 and a cam disk 25 which is fixedly connectedwith the bushing 21, there is disposed a cam 26 which is journalled onthe bushing. The cam 26 is coupled with the cam disk 25 by means of aspring. A split ring 27 secures the cam disk 25 and .therewith the cam26 in assigned position on the arbor 3.

The gear wheel 22 meshes with a pinion 23 which is journalled upon thespindle 2. A carrier member 29 is connected with the pinion 28 forrotation therewith, the member 29 carrying at its opposite ends spindlesindicated at 30 and 31, such spindles carrying brake shoes or weights 32and 33 which are journalled thereon. A looped spring 34 extends belowthe carrier 29 about the spindle 2 out of'engagement with the spindle,the looped spring having angular extensions 35 entering grooves formedin the brake shoes. The looped spring secures the brake shoes againstslipping off from the spindles 3%, 3-1, thus obviating holding meanssuch as separate split rings or the like.

There are provided two sets of contacts respectively comprising thenormal springs 37, 38 and the impulse springs 39, 40 which extend froman insulating member 36' mounted upon the base 1. The normal contacts(springs 37, 38) are controlled by a cam member 41 carried by the gearwheel 17-, the impulse spring til is in engagement with the impulse camof the impulse transmitting dcvice. Brackets 42 and 43 servefor mountingthe transmitter mechanism in a telephone set.

On the side facing the finger disk 8, the frame 1 is provided with a cap44 made of insulating material, which is snapped in place by means ofteeth such as 45 engagbushing, in opposite sense.

3 ing angular portions at the rim of the frame. The cap 44 carries therequired numerals and/ or characters such as indicated at 46. The fingerstop 47 is also made of insulating material, the mounting part of suchstop pro-- jecting through a slot formed in the cap 44 and being se--cured to the frame 1 against removal therefrom and against angulardisplacement relative thereto, by means of a screw 49 projecting througha hole formed in the .frame 1 and a nut 48 positioned in a recess formedin 'the cap 44. This mounting for the finger stop also se cures the cap44 against angular displacement and loosen,- ing thereof. The free end50 of the screw 49 projects; through and beyond the cap 44 in thedirection of the finger disk, forming a fixed stop for cooperation witha; stop 51 carried by the finger disk and movable therewith- Thestopping of the drive gear is effected by the cooperation of these stopsvery gently because the mass forcesi involved are controlled at a pointof greatest magnitude; thereof.

The journal or bearing surfaces and the gear wheels; and pinions as wellas the bushing 21, cam 26 and cam. disk 25 are made of non-metallicsynthetic material. The cam 41 for the actuation of the gear wheel17 isformed. integral with the coating of synthetic material carried by themetal body.

The operation of the dial is as follows:

Upon rotating the finger disk 8 out of its normal position, therestoring spring 13 will be wound up. The gear Wheel 17 will be carriedalong in such rotation, in turn. carrying along and rotating the pinion20 and the bushing 21' axially extending therefrom. The cam disk 25which.

is fixedly connected with the bushing 21 and the cam 26 which isfrictionally coupled with the cam disk 25, are likewise rotated. Thegear wheel 22 is coupled to the bushing 21, by the clutch spring 23,' sothat it is not rotated at all or only slightly displaced incident to thedescribed winding-up rotation of the parts. The cam 26 upon being takenalong is placed underneath the spring 40 and remains in such positiondue to its slight impositive coupling with the cam disk 25. The contactpoints of the impulse springs 39, 4%) are in engagement and thesesprings are in their engaged position moved back and forth in commonincident to the winding-up rotation of the finger disk but the contactengagement remains undisturbed. Accordingly, no impulses will betransmitted.

Upon rotation of the finger disk 8 from the wound-up 1 position back tonormal, the gear wheel 17 will rotate the pinion 2t) and therewith thebushing 21 extending therefrom and also the cam disk 25 connected withthe The gear wheel 22 is now taken along by the action of thecylindrical spring clutch 23 and drives the governor by rotating thepinion 28. The cam 26 upon being taken along arrives at the front edgeof the spring 40, which is slotted, one of the tongues which are formedby the slotting being shorter than the other. The spring 39 now lieswith its free end above the cam which had been stopped in front of theshorter tongue. Rotation of the cam disk 25 now causes alternate openingand closing of the contact points carried by the impulse springs 39, 40because spring 39 is held by cam 26 against following the motionsimparted to spring 40. In the normal or resting position of the fingerdisk 8, the contact points of springs 37, 38 will be out ofengagementdue to the action of cam 41 carried by the gear wheel 17. When thefinger disk is rotated out of its normal position, the contact springs37, 38 will be actuated to close their contact points up to the timewhen the finger disk returns to its normal position, when the contactswill again be opened.

The transmitter mechanism is covered at the bottom thereof by atransparent cap 52, made of resilient material, such cap being providedwith brackets 53 for snap-on engagement with corresponding mountingmeans carried by the frame 1.

Changes may be made within the scope and spirit of the appended claimsin which is defined what is believed to be new and desired to haveprotected by Letters Patent.

We claim:

1. A telephone call transmitter comprising a frame, a first and a secondspindle, each fixedly fastened at one end to said frame and freelyextending in parallel relationship therefrom, impulse contact meansdisposed adjacent to but spaced from said first fixed spindle, cam meansrotatably disposed on said first fixed spindle operatively related tosaid contact means for actuating the same, and a first pinion alsodisposed upon such spindle for drin'ng said cam means to eifectoperative actuation of said contact means, a governor rotatably disposedupon such second fixed spindle and a second pinion also disposed uponsuch second spindle for driving said governor, a rotatable main shaft, afinger disk rotatable with said main shaft, a first toothed gear wheelcarried by said rotatable main shaft, said first gear wheel meshing withsaid first pinion, and a second toothed gear wheel rotatably disposedupon said first spindle, said second toothed gear meshing with saidsecond pinion and operatively connecting the latter l to said firstpinion.

2. A call transmitter according to claim 1, wherein said frame is adiecast part having the respective ends of said first and secondspindles embedded therein and form- :ing an integral part thereof.

3. A call transmitter according to claim 1, comprising rneans forming araceway for said governor, and a device for mounting said raceway means,said device comprising .an extension integral with said frame andapproximately semi-circularly surrounding the spindle for said governor.

4. A call transmitter according to claim 3, wherein i said raceway meansis a stamped plate having a cylindrical [bore formed therein for brakingcooperation with a part of said governor.

5. A call transmitter according to claim 1, comprising a bushingextending axially from said first pinion integral therewith, a cam diskcarried by said bushing for rotation therewith, means for coupling saidsecond gear Wheel for rotation with said bushing, and a cam coupled forrotation with said bushing.

6. A call transmitter according to claim 1, wherein the journal surfacesof said gear wheels and those of :said pinions are formed bynon-metallic synthetic material.

7. A call transmitter according to claim 6, comprising a controlcontact, and a cam member for governing the actuation of said controlcontact, said cam member being formed integral with the syntheticmaterial of one of said gear wheels.

8. A call transmitter according to claim 1, wherein said main shaftcarries a jacket of non-metallic synthetic material.

9. A call transmitter according to claim 1, comprising a restoringspring, a casing rotatable with said main shaft, said casing containingsaid restoring spring, the ends of said restoring spring beingrespectively anchored in said frame and in said casing, and extensionsprojecting from said easing into openings formed in said first gearwheel main shaft.

References Cited in the file of this patent UNITED STATES PATENTS2,189,944 Field -r Feb. 13, 1940

